CVE-2024-20434 in IOS XE
Summary
by MITRE • 09/25/2024
A vulnerability in Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on the control plane of an affected device.
This vulnerability is due to improper handling of frames with VLAN tag information. An attacker could exploit this vulnerability by sending crafted frames to an affected device. A successful exploit could allow the attacker to render the control plane of the affected device unresponsive. The device would not be accessible through the console or CLI, and it would not respond to ping requests, SNMP requests, or requests from other control plane protocols. Traffic that is traversing the device through the data plane is not affected. A reload of the device is required to restore control plane services.
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Analysis
by VulDB Data Team • 09/29/2024
This vulnerability exists within Cisco IOS XE Software and represents a significant denial of service threat targeting the control plane functionality of affected network devices. The flaw stems from inadequate processing of frames containing VLAN tag information, creating a condition where maliciously crafted network traffic can disrupt critical system operations. An attacker positioned in the same network segment can exploit this weakness without requiring authentication credentials, making it particularly dangerous in environments where physical network access is possible. The vulnerability specifically impacts the control plane components that manage device configuration, monitoring, and administrative functions rather than the data plane that handles normal traffic forwarding operations.
The technical mechanism of exploitation involves sending specially crafted network frames with malformed or unexpected VLAN tagging information to the affected device. When the system processes these frames, the improper handling of VLAN tag data causes the control plane to become unresponsive, effectively disabling all administrative access methods including console connections, command line interfaces, and network management protocols. This vulnerability falls under the category of improper handling of network protocol data, which aligns with CWE-129 and CWE-704 classifications related to improper handling of input data and inadequate input validation. The attack vector requires an adjacent network position, meaning the attacker must be on the same broadcast domain as the target device, which is consistent with network layer attacks that exploit local network conditions.
The operational impact of this vulnerability extends beyond simple service disruption to create complete administrative paralysis of the affected device. Network administrators lose all means of accessing the device for troubleshooting, configuration changes, or monitoring purposes, while the device becomes unresponsive to standard network management protocols such as SNMP, ICMP pings, and other control plane communication methods. This condition renders the device effectively unusable for network operations until manual intervention occurs through a device reload or reboot. The requirement for a full system restart to restore functionality creates significant operational challenges, particularly in mission-critical network environments where uptime and availability are paramount. The vulnerability demonstrates how control plane attacks can completely compromise device management capabilities while leaving data plane operations unaffected, a pattern commonly observed in network infrastructure security flaws.
Mitigation strategies for this vulnerability should focus on network segmentation and access control measures to prevent unauthorized physical access to network devices. Implementing proper VLAN configuration controls and network access control lists can help limit the exposure of critical devices to potential attackers. Cisco has released software updates addressing this vulnerability, and organizations should prioritize applying these patches to affected systems. Network administrators should also consider implementing monitoring solutions that can detect unusual network traffic patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this type of vulnerability under network infrastructure attacks, specifically targeting control plane components that manage device operations and configuration. Regular network audits and vulnerability assessments should include checks for proper VLAN handling and control plane resilience to prevent similar issues from occurring in other network infrastructure components.